This invention is directed to a mobile robot that, by magnetic force, maintains operational contact with metal surfaces of the work piece over which it moves. The robot carries magnets displaced from the work piece an optimal distance related to the maximum magnetic flux between the robot and the work piece.
The robot carries attachments to strip, clean, refurbish and/or recondition the surface as it moves across the work piece. These attachments have structure and subsequent treatments that render the entire operation environmentally safe.
The robot can be used to refurbish any stationary or movable structures made of a metal having magnetic properties, such as buildings and vehicles. These structures include but are not limited to any iron or steel clad buildings, bridges, tunnels, pipe lines, ships, trains, cars, trucks, and military vehicles of all types.
Mobile robots that have magnetic wheels in contact with the surface upon which they work are conventional. However, the movement of some of the robots across the metal surface caused ancillary damage to the surface in the area of contact. Because of the rigidity of the magnetic wheels and the magnetic force between the wheels and the rigid work surface, the paint or protective coatings on the work piece are crushed.
The prior art robots were not capable of treating the entire surface of the structures upon which they were attached because the working head or heads are located inboard of the wheels.
This invention is directed toward elimination of these characteristics of the prior art devices. Specifically, the magnets of this invention are not in contact with the work piece. Also, the working heads are located to allow the heads to extend to or beyond the margins of the work piece.
U.S. Pat. No. 5,628,271 and U.S. Pat. No. 5,849,099 both disclose a mobile robot for striping the hulls of ships. The robots have a chassis mounted on four wheels made of magnets. The chassis carries a rotary head enclosed in a chamber which applies water to the hull at approximately 30,000 pounds per square inch. The chamber is subjected to a negative pressure to remove the water and residue.
The magnetic force exerted directly upon the surface of the hull is sufficient to support the weight of the robot and overcome the force of the high pressure water impinging on the hull. The pressure created by the magnetic force is transmitted to the hull through the area of contact with the wheels. Since the wheels are made of a rigid magnetic metal, the area is confined to the tangential contact of the hull and the wheel. At any given moment, the entire magnetic force holding the hull and the robot together is transmitted by the foot print of the wheels which is, basically, four lines with a length representing the width of each wheel and a width representing the tangential contact between the circumference of the metal wheel and the plane of the metal hull.
The magnetic attraction between the wheels and the hull is of such magnitude directed through such minimal contact that the metal wheels crush and permanently damage the paint or protective coating between the wheels and the hull.
With the magnetic wheels placed at the four corners of the chassis, the high pressure rotary head could not be maneuvered to engage the entire surface of the hull, particularly the margins.
Accordingly, it is an objective of the instant invention to provide a magnetic mobile robot for traversing the surface of a work piece without damaging the protective coatings on the surface of the work piece as a result of contact between the robot and the surface.
It is a further objective of the instant invention to provide a magnetically supported mobile robot with working heads which clean, strip, recondition and/or refurbish the surface of a work piece
It is yet another objective of the instant invention to provide an environmentally safe protective structure about the working heads that prevents escape of debris from the robot. The protective structure additionally guides the waste products into return lines for further processing.
It is another objective of the invention to treat the waste products by separation from the cleaning fluid and recycling the cleaning fluid through the working heads. The separated waste products are reduced by an environmentally safe process to a harmless by-product.
It is a still further objective of the invention to teach an environmentally safe process of stripping accretions, deposits, plant and animal forms, and protective coatings from magnetically active metal surfaces and disposing of the waste products.
Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.